I can relate to this.
It's the engine which is so strong @ low revs.
Downtown taking miniroundabouts in 3rd most of the time.< 20 mph.
I had this a few times taking a miniroundabout I thought: Less thrust than normal. wth? It was in 4th.... Just my own laziness, not thinking about spirited driving at all sometimes.
I think it's best to keep it above 1500rpm in general for the engine's sake...